Oh, make no mistake about it, Cameron can be pressured into doing the right thing.
What is the 'right thing'?
I would go with what is proposed in the latest news, ie a greater number of Syrians but offered asylum directly from the UN refugee camps as that ensures the people receiving asylum are genuine asylum seekers and not economic migrants. I hope that is the line Cameron takes rather than opening the doors to those who have come through Europe because that will just encourage the traffickers and the economic migrants.
I would also be very careful as to the numbers. I notice that local councils have said any refugees must be 'fully funded' by central government. Now there's a surprise.